Spectral Flow Cytometry Methods and Pipelines for Comprehensive Immunoprofiling of Human Peripheral Blood and Bone Marrow

Profiling hematopoietic and immune cells provides important information about disease risk, disease status, and therapeutic responses. Spectral flow cytometry enables high-dimensional single-cell evaluation of large cohorts in a high-throughput manner. Here, we designed, optimized, and implemented new methods for deep immunophenotyping of human peripheral blood and bone marrow by spectral flow cytometry. Two blood antibody panels capture 48 cell-surface markers to assess more than 58 cell phenotypes, including subsets of T cells, B cells, monocytes, natural killer (NK) cells, and dendritic cells, and their respective markers of exhaustion, activation, and differentiation in less than 2 mL of blood. A bone marrow antibody panel captures 32 markers for 35 cell phenotypes, including stem/progenitor populations, T-cell subsets, dendritic cells, NK cells, and myeloid cells in a single tube. We adapted and developed innovative flow cytometric analysis algorithms, originally developed for single-cell genomics, to improve data integration and visualization. We also highlight technical considerations for users to ensure data fidelity. Our protocol and analysis pipeline accurately identifies rare cell types, discerns differences in cell abundance and phenotype across donors, and shows concordant immune landscape trends in patients with known hematologic malignancy.

SIGNIFICANCE

This study introduces optimized methods and analysis algorithms that enhance capabilities in comprehensive immunophenotyping of human blood and bone marrow using spectral flow cytometry. This approach facilitates detection of rare cell types, enables measurement of cell variations across donors, and provides proof-of-concept in identifying known hematologic malignancies. By unlocking complexities of hematopoietic and immune landscapes at the single-cell level, this advancement holds potential for understanding disease states and therapeutic responses.

Clonal barcoding with qPCR detection enables live cell functional analyses for cancer research

Single-cell analysis methods are valuable tools; however, current approaches do not easily enable live cell retrieval. That is a particular issue when further study of cells that were eliminated during experimentation could provide critical information. We report a clonal molecular barcoding method, called SunCatcher, that enables longitudinal tracking and live cell functional analysis. From complex cell populations, we generate single cell-derived clonal populations, infect each with a unique molecular barcode, and retain stocks of individual barcoded clones (BCs). We develop quantitative PCR-based and next-generation sequencing methods that we employ to identify and quantify BCs in vitro and in vivo. We apply SunCatcher to various breast cancer cell lines and combine respective BCs to create versions of the original cell lines. While the heterogeneous BC pools reproduce their original parental cell line proliferation and tumor progression rates, individual BCs are phenotypically and functionally diverse. Early spontaneous metastases can also be identified and quantified. SunCatcher thus provides a rapid and sensitive approach for studying live single-cell clones and clonal evolution, and performing functional analyses.

Abstract 1702: SunCatcher: Clonal barcoding with qPCR-based detection enables live cell functional analyses and generation of custom cell pools

Single cell “omics” and lineage tracing analyses are valuable tools for studying heterogeneity and clonal dynamics. However, current clonal analyses do not easily enable live cell retrieval. That is a particular issue when further study of cells that were targeted for elimination or otherwise not selected during an experiment could provide critical information. We report a clonal molecular barcoding method, called SunCatcher, that enables longitudinal tracking and retrieval of live cells. Single cell-derived clonal populations are generated from complex cell population, each is infected with a unique, heritable molecular barcode, and stocks of each individual barcoded clone (BC) are retained. BCs can be combined to create a version of the original cell population or to generate custom BC pools. We developed a highly sensitive, accurate, rapid, and inexpensive qPCR-based method for identifying and quantifying BCs in vitro and in vivo.We applied SunCatcher to various breast cancer cell lines, including murine Met1 triple negative breast cancer line. A heterogeneous pool comprised of 31 Met1 BCs reliably reproduced the proliferation rate, tumor-forming capacity, and cancer progression as the original parental cell line. Individual BCs, however, displayed significant differences in proliferation, tumor formation, and breast cancer cell hallmarks: cytokeratin 8/14, Zeb1 (mesenchymal marker), EpCAM (epithelial marker) PD-L1 (immune checkpoint protein) and MHC-I (antigen presentation). Five BCs consistently dominated the primary tumors at the ethical end point of 21 days: BC2, BC8, BC25, BC53, BC67. Interestingly, not all 5 BCs were the fastest growing clones, suggesting in vitro proliferation does not correlate with clone expansion in vivo. Two clones (BC43, 18) were not detected in the primary tumors at ethical endpoint, yet when injected alone, had tumor-forming capacity after a long latency (~60 days). Therefore, SunCatcher enabled identification of clones that are consequential for disease progression that would otherwise not be identified during pre-clinical experimentation. Using SunCatcher, we successfully detected Met1 spontaneous metastases as early as 3 weeks in the lung, long bone, and mandible. Long bone had the highest incidence and metastatic burden and were dominated by BC53 and 8 in 3/5 mice. Lung had lower metastatic burden and BC53 was the dominant clone in 4/4 mice. BC8 was exclusive to bone, suggesting site-specific metastasis capacity for different tumor clones. SunCatcher is a reliable, inexpensive, and rapid clonal barcoding method that enables deeper understanding of heterogeneity and clonal dynamics. We identified and analyzed BCs that were responsible for cancer progression, and, for the first time, could analyze BCs that were negatively selected during cancer progression. We envision that SunCatcher will be a useful cancer research tool.

Citation Format: Qiuchen Guo, Milos Spasic, Adam Maynard, Gregory Goreczny, Amanuel Bizuayehu, Jessica Olive, Sandra McAllister. SunCatcher: Clonal barcoding with qPCR-based detection enables live cell functional analyses and generation of custom cell pools [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1702.

Abstract 1773: Overcoming paclitaxel resistance in triple-negative breast cancer using a novel barcoding technology

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype for which chemotherapy remains a part of standard treatment. Although pathologic complete response (pCR) after neoadjuvant chemotherapy, including paclitaxel (PTX), is associated with good outcomes, 50-60% of TNBC patients do not experience pCR and suffer poor long-term outcomes, often due to chemotherapy resistance. Identifying and analyzing the tumor cells responsible for chemotherapy resistance will lead to improved treatment strategies.

We developed a model of TNBC resistance to neoadjuvant PTX using Met1 murine mammary carcinoma cells. To study clonal dynamics in response to PTX we developed a barcoding method, SunCatcher. First, 31 single-cell derived clonal populations were generated from parental Met1 cells. Each clone was infected with a lentiviral vector containing a unique DNA barcode detectable by qPCR. All barcoded clones (BCs) were mixed in equivalent numbers to generate a BC pool that we confirmed captures the parental Met1 heterogeneity and tumor growth kinetics.

First, PTX responses were tested in vitro. The BC pool had an IC50 of ~100 nM, while individual BCs ranged in IC50 from 5 nM to 25 µM. We maintained the BC pool in 100 nM PTX for 39 days (termed long-term PTX; LTP), at which point it became clonal for BC25, suggesting that BC25 (IC50 of 100 nM) is uniquely PTX resistant, despite being the most proliferative and Zeb1hi/EpCAMlow clone in vitro. BC25 was not detected in the control-treated BC pool at 39 days.

Next, the BC pool was orthotopically injected into FVB/NJ mice and treated the mice with 20 mg/kg PTX on days 7, 11, and 15. At the day 18 experimental endpoint, tumor volume significantly decreased by 56% in response to PTX compared to control. BC25 composition increased from 7.7% (controls) to 15% (PTX treated) within the tumors at endpoint. We also injected BC25 and LTP cells alone and administered the same PTX regimen once tumors reached 50 mm3. Both BC25 and LTP tumors were unresponsive to PTX and had a longer latency period (35d) than BC pool (10d).

We performed a drug screen of 2313 compounds spanning FDA-approved cancer therapeutics on the LTP cells to identify compounds to target the PTX-resistant clone. HDAC inhibitors were the most potent class of hits and one, Panobinostat, killed LTP cells with an IC50 of 4.3 nM.

Utilizing SunCatcher, we identified a unique PTX-resistant TNBC subclone that represents residual disease associated with poor long-term outcome. Typical in vivo experiments would have reached ethical endpoint before BC25 had a chance to grow, given its long latency, therefore this PTX-resistant clone would not have been identified. This is an important finding because therapeutic resistance can emerge after a protracted period, longer than typical pre-clinical experiments. Further work will explore mechanisms of resistance and the potential for combination therapies to prevent recurrent disease.

Citation Format: Milos Spasic, Qiuchen Guo, Adam Maynard, Gregory Goreczny, Adrienne Waks, Sara Tolaney, Elizabeth Mittendorf, Sandra McAllister. Overcoming paclitaxel resistance in triple-negative breast cancer using a novel barcoding technology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1773.

Fenoldopam Sensitizes Primary Cilia-Mediated Mechanosensing to Promote Osteogenic Intercellular Signaling and Whole Bone Adaptation

Bone cells actively respond to mechanical stimuli to direct bone formation, yet there is no current treatment strategy for conditions of low bone mass and osteoporosis designed to target the inherent mechanosensitivity of bone. Our group has previously identified the primary cilium as a critical mechanosensor within bone, and that pharmacologically targeting the primary cilium with fenoldopam can enhance osteocyte mechanosensitivity. Here, we demonstrate that potentiating osteocyte mechanosensing with fenoldopam in vitro promotes pro-osteogenic paracrine signaling to osteoblasts. Conversely, impairing primary cilia formation and the function of key ciliary mechanotransduction proteins attenuates this intercellular signaling cascade. We then utilize an in vivo model of load-induced bone formation to demonstrate that fenoldopam treatment sensitizes bones of both healthy and osteoporotic mice to mechanical stimulation. Furthermore, we show minimal adverse effects of this treatment and demonstrate that prolonged treatment biases trabecular bone adaptation. This work is the first to examine the efficacy of targeting primary cilia-mediated mechanosensing to enhance bone formation in osteoporotic animals. © 2022 American Society for Bone and Mineral Research (ASBMR).

Abstract 1561: Age impacts response to paclitaxel-anti-PDL1 combination therapy in triple-negative breast cancer

Over half of breast cancer patients are >60 years old, yet women >65 represent <20% of patients enrolled in clinical trials. Moreover, most preclinical breast cancer models use young mice that do not represent the age of most patients. This raises the question of whether real world practice will reflect preclinical and clinical trial results. Recently, the IMpassion031 trial, evaluating neoadjuvant nab-paclitaxel +/- anti-PD-L1 in TNBC, reported significantly improved pathological complete response rates. Given that immune function declines with age, it is critical to understand how response to immunotherapies is impacted by age. Therefore, we designed a preclinical TNBC study to understand whether age impacts response to neoadjuvant paclitaxel +/- anti-PD-L1.

Immunologically Young (~8 week old) and Aged (~12 month old) FVB/NJ mice were orthotopically injected with Met1 TNBC cells. When tumors became palpable, mice were treated with paclitaxel or vehicle control (days 7, 11, 15) and either anti-PD-L1 or isotype control (days 8, 11, 14), and sacrificed on day 16. Blinded tumor measurements were performed to quantify tumor volume and mass. Tumor sections were histologically analyzed for tumor infiltrating lymphocytes. We also analyzed peripheral blood counts, bone marrow progenitor cells, and bulk RNA sequencing of primary tumors.

Aged cancer-free mice had fewer circulating CD4+ and CD8+ T cells. Tumor growth was slower in aged mice, reflecting the fact that TNBC is more aggressive in young women. While paclitaxel reduced tumor growth in both young and aged mice, addition of anti-PD-L1 therapy further reduced tumor growth only in young mice; this benefit was lost in aged mice. Similarly, IMpassion031 trial trends suggest younger women benefit more from addition of anti-PD-L1 to chemotherapy. Tumors from aged untreated mice had more infiltrating T regulatory cells and did not exhibit the same increases in infiltrating T-cells that occured with anti-PD-L1, paclitaxel, or combination therapy in young mice. Utilizing a unique molecular barcoding approach we identified populations of tumor cells resistant to therapy in an age-depedent manner. Finally, RNA sequencing analysis is ongoing and should provide insights into mechanisms driving age-dependent therapy responses.

Our results indicate that age is a critical component of the T-cell inflamed phenotype and response to combination chemotherapy + anti-PD-L1. Our preclinical model captures immunological age and mimics therapeutic responses to neoadjuvant chemotherapy+ICB shown in clinical trials. By identifying populations of tumor cells contributing to age-dependent therapeutic responses, we gain critical insights into molecular mechanisms of tumor growth and resistance. Ultimately our work has the potential to guide age-stratified treatment strategies for patients not accurately represented in clinical trials.

Citation Format: Milos Spasic, Gregory J. Goreczny, Qiuchen Guo, John N. Hutchinson, Rachel A. Freedman, Elizabeth A. Mittendorf, Sandra S. McAllister. Age impacts response to paclitaxel-anti-PDL1 combination therapy in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1561.

Abstract 1955: Investigating anti-tumor immunity with CDK4/6 inhibition in triple negative breast cancer

The purpose of our study is to evaluate the immunological effects of CDK4/6 inhibitors in pre-clinical models of triple negative breast cancer (TNBC). CDK4/6 inhibitors, including abemaciclib, are currently approved to treat patients with metastatic hormone receptor-positive (HR+), Her2-negative breast cancer. We previously reported in our HR+ model that CDK4/6 inhibitors promote anti-tumor immunity by inducing tumor cell antigen presentation via activating tumor endogenous retroviral elements, which induce type III interferon production and MHC-I upregulation (Goel, DeCristo, et al., Nature, 2017). We also uncovered important anti-tumor effects on the immune system: CDK4/6 inhibitors decrease T regulatory cell proliferation without affecting cytotoxic CD8 T cell numbers. TNBC has been considered a poor candidate for CDK4/6 inhibitor therapy, as tumors often lose retinoblastoma (Rb) protein expression/function, which is critical for CDK4/6 inhibitor-induced cell cycle arrest. However, Rb mutation or loss occurs in only ~20% of TNBC cases and we found Rb expressing murine and human TNBC cell lines decreased proliferation in vitro in response to abemaciclib. In our preclinical model of TNBC, abemaciclib suppressed tumor growth Consistent with previous findings, TNBC tumor cells upregulated MHC-I upon abemaciclib treatment, suggesting increased antigen presentation. Tumor cell-surface PD-L1 was also increased with abemaciclib both in vitro and in vivo, as assessed by flow cytometry and RT-qPCR. These results are encouraging, given that αPD-L1 therapy (Atezolizumab) in combination with chemotherapy (nab-paclitaxel) has recently been approved as standard care for metastatic TNBC and the IMpassion130 trial reported enhanced progression-free and overall survival in patients with PD-L1+ tumors. However, treatment with Palbociclib did not increase tumor PD-L1 level, suggesting the potential functional variances between different CDK4/6 inhibitors. Our data therefore suggest the potential efficacy of abemaciclib in combination with αPD-L1 in the treatment of Rb+ TNBC. We also found that abemaciclib increased CD8+ and CD4+ T cells and decreased PD1+ CD8 and CD4 cells in the spleen. Furthermore, total numbers of naïve CD8+ and CD4+ T cells increased with abemaciclib treatment, suggesting a favorable anti-tumor systemic immunological effect. We recently performed RNAseq on abemaciclib-treated TNBC and while we do not have the results at this time, they will be analyzed and prepared for presentation at the meeting. Deeper analysis of the mechanisms involved in regulation of PD-L1 expression and enhancement of naïve T cells should enable us to evaluate combination therapies using CDK4/6 inhibitors for this particularly deadly breast cancer subtype.

Citation Format: Qiuchen Guo, Milos Spasic, Gregory Goreczny, Adam Maynard, Sandra McAllister. Investigating anti-tumor immunity with CDK4/6 inhibition in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1955.

Abstract PS17-49: Investigating CDK4/6 inhibition in triple negative breast cancer

The purpose of our study is to evaluate the immunological effects of CDK4/6 inhibitors in pre-clinical models of triple negative breast cancer (TNBC). CDK4/6 inhibitors, including abemaciclib, are currently approved to treat patients with metastatic hormone receptor-positive (HR+), Her2-negative breast cancer. We previously reported in our Her2+ model that CDK4/6 inhibitors promote anti-tumor immunity through inducing tumor cell antigen presentation via activating tumor endogenous retroviral elements, which induce type III interferon production and MHC-I upregulation (Goel, DeCristo, et al., Nature, 2017). We also uncovered important anti-tumor effects on the immune system: CDK4/6 inhibitors decrease T regulatory cell proliferation without affecting cytotoxic CD8 T cell numbers. TNBC has been considered a poor candidate for CDK4/6 inhibitor therapy, as tumors often lose retinoblastoma (Rb) protein expression/function, which is critical for CDK4/6 inhibitor-induced cell cycle arrest. However, Rb mutation or loss occurs in only ~20% of TNBC cases and we found Rb expressing murine and human TNBC cell lines decreased proliferation in vitro in response to abemaciclib. In our preclinical model of TNBC, abemaciclib induced tumor regression. Consistent with previous findings, TNBC tumor cells upregulated MHC-I upon abemaciclib treatment, suggesting increased antigen presentation. Tumor cell-surface PD-L1 was also increased with abemaciclib both in vitro and in vivo, as assessed by flow cytometry and RT-qPCR. These results are encouraging, given that αPD-L1 therapy (Atezolizumab) in combination with chemotherapy (nab-paclitaxel) has recently been approved as standard care for metastatic TNBC and the IMpassion130 trial reported enhanced progression-free and overall survival in patients with PD-L1+ tumors. We also found that abemaciclib increased CD8+ and CD4+ T cells and decreased PD1+ CD8 and CD4 cells in the spleen. Furthermore, total numbers of naïve CD8+ and CD4+ T cells increased with abemaciclib treatment, suggesting a favorable anti-tumor systemic immunological effect. Our data suggest the potential efficacy of CDK4/6 inhibitors in combination with αPD-L1 in the treatment of Rb+ TNBC. Deeper analysis of the mechanisms involved in regulating PD-L1 and enhancing naïve T cells should enable us to evaluate combination therapies using CDK4/6 inhibitors for this particularly deadly breast cancer subtype.

Citation Format: Qiuchen Guo, Gregory J Goreczny, Milos Spasic, Adam Maynard, Sandra S McAllister. Investigating CDK4/6 inhibition in triple negative breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS17-49.

The ESC ACCA EAPCI EORP acute coronary syndrome ST-elevation myocardial infarction registry

Aims 

The Acute Cardiac Care Association (ACCA)–European Association of Percutaneous Coronary Intervention (EAPCI) Registry on ST-elevation myocardial infarction (STEMI) of the EurObservational programme (EORP) of the European Society of Cardiology (ESC) registry aimed to determine the current state of the use of reperfusion therapy in ESC member and ESC affiliated countries and the adherence to ESC STEMI guidelines in patients with STEMI.

Methods and results 

Between 1 January 2015 and 31 March 2018, a total of 11 462 patients admitted with an initial diagnosis of STEMI according to the 2012 ESC STEMI guidelines were enrolled. Individual patient data were collected across 196 centres and 29 countries. Among the centres, there were 136 percutaneous coronary intervention centres and 91 with cardiac surgery on-site. The majority of centres (129/196) were part of a STEMI network. The main objective of this study was to describe the demographic, clinical, and angiographic characteristics of patients with STEMI. Other objectives include to assess management patterns and in particular the current use of reperfusion therapies and to evaluate how recommendations of most recent STEMI European guidelines regarding reperfusion therapies and adjunctive pharmacological and non-pharmacological treatments are adopted in clinical practice and how their application can impact on patients’ outcomes. Patients will be followed for 1 year after admission.

Conclusion 

The ESC ACCA-EAPCI EORP ACS STEMI registry is an international registry of care and outcomes of patients hospitalized with STEMI. It will provide insights into the contemporary patient profile, management patterns, and 1-year outcome of patients with STEMI.

Primary cilia: Cell and molecular mechanosensors directing whole tissue function

Primary cilia are immotile, microtubule-based organelles extending from the surface of nearly every mammalian cell. Mechanical stimulation causes deflection of the primary cilium, initiating downstream signaling cascades to the rest of the cell. The cilium forms a unique subcellular microdomain, and defects in ciliary protein composition or physical structure have been associated with a myriad of human pathologies. In this review, we discuss the importance of ciliary mechanotransduction at the cell and tissue level, and how furthering our molecular understanding of primary cilia mechanobiology may lead to therapeutic strategies to treat human diseases.

Lengthening primary cilia enhances cellular mechanosensitivity

The primary cilium is a mechanosensor in a variety of mammalian cell types, initiating and directing intracellular signalling cascades in response to external stimuli. When primary cilia formation is disrupted, cells have diminished mechanosensitivity and an abrogated response to mechanical stimulation. Due to this important role, we hypothesised that increasing primary cilia length would enhance the downstream response and therefore, mechanosensitivity. To test this hypothesis, we increased osteocyte primary cilia length with fenoldopam and lithium and found that cells with longer primary cilia were more mechanosensitive. Furthermore, fenoldopam treatment potentiated adenylyl cyclase activity and was able to recover primary cilia form and sensitivity in cells with impaired cilia. This work demonstrates that modulating the structure of the primary cilium directly impacts cellular mechanosensitivity. Our results implicate cilium length as a potential therapeutic target for combating numerous conditions characterised by impaired cilia function.

Sport specific fitness status in junior water polo players--Playing position approach

AIM

The aim of this investigation was to study the physical fitness differences between two qualitative levels of junior water polo players, with regard to their playing positions.

METHODS

The sample (N.=54, males; 16-18 years of age) comprised 13 members of the Junior National Squad (JNS; 5 centres and 8 perimeter players), and 41 team athletes (TA; 11 centres and 30 perimeter players). The sample of variables included: body height, body mass, BMI and body fat percentage, 20 metres sprint swimming, maximal dynamometric force in eggbeater kick (DF), on-water vertical jump, drive-shoot-speed, and swimming-endurance-test (SET). Differences between JNS and TA were analysed by t-test for independent samples and by a magnitude-based Cohen's effect size (ES) statistic with modified qualitative descriptors. Forward conditional logistic regression (FCLR) was calculated to determine the impact of the physical fitness variables on the dichotomous criterion (JNS vs. TA).

RESULTS

All variables were found to be reliable. The JNS perimeter players performed better (P<0.05) in SET, DF, and sprint-swimming than the TA perimeter players. No significant differences were found for centres. FCLR revealed drive-shoot-speed as the only significant predictor of qualitative level (Y=-12.925 + 1.188 * DSHOOT; OR: 1.023-1.380) CONCLUSION: Fitness capacities are more important as determinants of quality among perimeters than among centres. The results highlight the need for position-specific training programmes in junior water polo.

Adenylyl cyclase 6 mediates loading-induced bone adaptation in vivo

Primary cilia are single, nonmotile, antenna-like structures extending from the apical membrane of most mammalian cells. They may mediate mechanotransduction, the conversion of external mechanical stimuli into biochemical intracellular signals. Previously we demonstrated that adenylyl cyclase 6 (AC6), a membrane-bound enzyme enriched in primary cilia of MLO-Y4 osteocyte-like cells, may play a role in a primary cilium-dependent mechanism of osteocyte mechanotransduction in vitro. In this study, we determined whether AC6 deletion impairs loading-induced bone formation in vivo. Skeletally mature mice with a global knockout of AC6 exhibited normal bone morphology and responded to osteogenic chemical stimuli similar to wild-type mice. Following ulnar loading over 3 consecutive days, bone formation parameters were assessed using dynamic histomorphometry. Mice lacking AC6 formed significantly less bone than control animals (41% lower bone formation rate). Furthermore, there was an attenuated flow-induced increase in COX-2 mRNA expression levels in primary bone cells isolated from AC6 knockout mice compared to controls (1.3±0.1- vs. 2.6±0.2-fold increase). Collectively, these data indicate that AC6 plays a role in loading-induced bone adaptation, and these findings are consistent with our previous studies implicating primary cilia and AC6 in a novel mechanism of osteocyte mechanotransduction.

Expression analysis of genes involved in apoptosis, proliferation and endoplasmic reticulum stress in ionomycin/PMA treated Jurkat cells

PURPOSE

Activation of T cells by direct stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin (Io) results in numerous downstream signals that activate pathways enabling T cells to proliferate and produce cytokines. Inducible T cell activation is regulated predominantly at the transcriptional level. Therefore, we were interested to analyze the transcriptional activity of the 19 genes involved in the regulation of several important cellular processes.

METHODS

Quantitative real-time (RT) PCR analysis was performed using mRNA-specific primers and SybrGreen for relative mRNA expression levels of all the examined genes.

RESULTS

Our results showed c-kit expression in Jurkat cells, further confirmed by sequencing of c-kit mRNAspecific PCR product. The expected increased expression of interleukin (IL)-2 mRNA, together with moderate Ki-67 upregulation, indicate the proliferation of PMA/Io treated Jurkat cells. Significant upregulation of nuclear factor (NF)-κB, JNK and the prosurvival Bcl-2 was followed by activation of only one protein kinase RNA-like endoplasmic reticulum kinase (PERK) out of 3 main endoplasmic reticulum (ER) stress subpathways (ATF6 and spliced XBP were downregulated). NF-κB and JNK activation, as well as ERK downregulation were reactive oxygen species (ROS)-independent, shown by the lack of activation of antioxidative enzymes (SOD, NOS, GSTP1, gGCS and GR). C-kit was downregulated in the absence of exogenous SCF (c-kit ligand).

CONCLUSION

Based on these data it is concluded that the PMA/Io treatment of Jurkat cells induced increased expression of IL-2, followed by upregulation of prosurvival genes belonging to the Bcl-2 family. Neither c-kit nor the antioxidative system were activated, excluding their role in Jurkat T-cell activation in the absence of exogenous c-kit ligand SCF.

The effect of selenium on antioxidant system in erythrocytes and liver of the carp (Cyprinus carpio L.)

The effect of selenium-supplemented diet (sodium selenate and selenium yeast) on antioxidant in erythrocytes and liver of the carp (Cyprinus carpio L.) fingerlings was studied. With this goal, the activities of glutathione peroxidase (GSH-Px), catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and glutathione-S-transferase (GST), as well as glutathione (GSH + GSSG) level, were determined. In the group supplemented with sodium selenate, no significant changes in the activity of the above enzymes were recorded in both the erythrocytes and in the liver, with the exception of GST activity that was significantly reduced in the plasma compared with the controls. Glutathione content was at the control level. In the group supplemented with selenium-yeast, the activities of GSH-Px, CAT, and SOD were significantly increased in erythrocytes, whereas GST activity and plasma content of GSH + GSSG were reduced compared with the controls. At the same time, the activities of hepatic SOD and GST were increased compared with the controls. These results demonstrate that organically bound selenium (selenium-yeast) acts more efficiently on antioxidant system of the carp fingerlings than inorganic selenium salts.

Antioxidant defenses in the ground squirrel Citellus citellus. 1. A comparison with the rat

The antioxidant defenses of the liver, erythrocytes, blood plasma, and interscapular brown adipose tissue (IBAT) of male ground squirrels were compared with those of male rats kept under identical conditions and fed the same diet. Superoxide dismutase (SOD), ascorbate, vitamin E, catalase, glutathione, and enzymes of glutathione metabolism were measured. In general, antioxidant defenses in erythrocytes were lower in ground squirrels than in rats. The same was true in liver, except that catalase-specific activity was higher. In IBAT, ascorbate, vitamin E, catalase, and glutathione reductase were higher than in rat and more of the SOD activity present was cyanide-insensitive (MnSOD). It is suggested that IBAT in ground squirrels may need a relatively greater antioxidant defense because of its important role in thermogenesis, especially in reawakening from hibernation. No major differences in antioxidant defenses between male and female ground squirrels were observed, except that the SOD activity of IBAT was higher in females.

Comparison of pharmacokinetic and cell binding properties of turkey Cu-SOD and E. coli Mn-SOD

The pharmacokinetics in rats and cell fixation properties of coli Mn-SOD are compared with those of Cu-SODs extracted from turkey blood. Despite similarities in molecular weight and pl the different enzymes show different characteristics. The results are discussed with respect to the mechanism of anti-inflammatory activity of superoxide dismutase.